Method of wool scouring with composition containing suint, alcohols, ketones, and inorganic electrolytes



patented Oct. 13, 1953 UNITED STATES METHOD OF WOOL SCOURING WITH COM- POSITION CONTAINING SUINT, ALCO- HOLS, KETONES, AND INORGANIC ELEC- TROLYTES Harold P. Lundgren, Berkeley, and Willie Fong, San Francisco, Calif., assignors to United States of America as represented by the Secretary of Agriculture No Drawing. Application March 27, 1950, Serial No. 152,271

6 Claims. 8-139) (Granted under This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described, if patented in any country, may be manufactured and used by or for the Government of the United States of America for governmental purposes throughout the world without any payment to us of any royalty thereon.

This invention relates to the processing of wool and has as its prime object the provision of improved methods for scouring raw wool.

Raw wool scouring is the preliminary step in the processing of wool in which the impurities present in the wool are removed by suitable physical or chemical means. The process is of great importance in the success of subsequent operations, such as carding, drawing, spinning, weaving, dyeing, etc.

The nature and the quantity of the impurities in raw wool vary, depending to a certain extent upon the breed of the animal and the geographical, climatic or nutritional conditions under which it is raised. Generally speaking, these impurities may be classified into two broad categories,

(I) acquired impurities, such as earthy material,

vegetable matter, faecal matter, paint, tar, etc., and (2) the natural impurities secreted by the animal.

These natural impurities consist of two major components, wool suint and wool grease. Together these two components are commonly known as wool yolk.

Wool suint is the dried, water-soluble material secreted by the sweat gland of the animal.

Chemically, very little is known concerning the exact composition of this substance; however, investigators agree that it consists essentially of the potassium salts of high molecular weight fatty acids. Wool suint possesses some detergent power which is utilized in the known aqueous scouring processes as will be explained hereinafter.

The wool grease is a complex water-insoluble mixture of fats and oils secreted by the sebaceous glands of the sheep. This material protects the wool fibers against the elements during its growth. Strictly speaking, the greasy component of wool is a wax, the ester of a high molecular weight monohydric alcohol and a fatty acid. The component wool wax alcohols consist of three major series: (1) the sterols, principally cholesterol, (2) the triterpene-like alcohols, principally lanosterol, and (3) aliphatic alcohols. The component wool wax acids consist of four major series: (1) the normal fatty acids, (2)

Title 35, U. S. Code (1952),

sec. 266) hydroxy acids, (3) branched chain acids, and (4) iso acids.

Commercially, the greater portion of the wool scoured in this country, as well as abroad, is accomplished by aqueous means in an alternating series of bowls and squeeze rolls through which the wool is propelled with a gentle mechanical action. In this aqueous process there are two basic systems known as the emulsification process and the Duhamel or suint process, respectively. In the emulsification process, soap or synthetic detergent and soda ash, added in varying amounts to all bowls except the final rinse bowl, perform the major scouring action. In the suint scouring process, the wool is first steeped in lukewarm water to dissolve the water-soluble suint salts. This suint solution is then clarified by filtering and centrifuging and returned to the first two bowls as the major scouring agent.

Neither the emulsification nor the suint process are entirely satisfactory for the following reasons. In the case of the emulsification process, the pH of the scouring solution is so high that there is danger or serious damage to the wool fibers. Further, the recovery of the byproducts, the suint and the wool grease, from the spent scouring liquor is difiicult. In the suint process the treatment is mild and does not damage the fibers but it does not reduce the grease content of the wool to the low levels required by the industry.

It has now been found that raw wool can be scoured by a simple and effective method. In essence, our process involves scouring the wool with water containing a neutral, polar, oxygenated organic compound and preferably containing a neutral electrolyte in addition to the organic compound. During the scouring treatment, the suint from the raw wool dissolves in the scouring medium and its effectiveness in emulsifying grease is enhanced by the presence of the afore-mentioned agent or agents. Thus our process is an improvement on the known suint process in that we utilize the emulsification properties of the suint which dissolve in the aqueous scouring medium but we increase the efiectiveness of this material. An advantage of the process of this invention is that we preserve the mild action of the suint process and at the same time increase its effectiveness so that the raw wool is scoured to form a finished. wool of low grease content as required in commerce.

The scoured wool produced in accordance with our process is not only low in residual grease content but is in a clean and lofty state and Furthermore, our scouring process is performed under mild conditions, at essentially-neutral pl-I,

and therefore the wool does not undergo chemi-- cal damage or loss in tensilestrength or resilience.

In our process, the additional of the neutral, polar, oxygenated organic compound, or organic compound plus neutral electrolytato thescour ing medium is believed toassis't the' removal'of" grease in two ways: (1) By enhancing micelle formation of the suint ions to assist in solubilizing the wool grease; (2) By removalof a protective water shell around the grease particles sothat the suint can more effectively remove the. grease by solubilization. These factors are further explained as follows:

(l) The chemical structure of the suint salts is similar to that of a typical soap, being characterized by a negatively chargedp'olaror Water compatible head and a long chain hydrocarbon or water incompatible tail; The suint salts are readily soluble in water and go. into solution as ions. Ordinarily, the suint ions tend to aggregate in water to someextentythe micelles which form consist of the hydrocarbon tails oriented togetherfiand thenegative heads forming an interface at the Water boundary. As many as to 50ions can be so i'n'volved. It is believed that the micelle form of the suint is capable of solubilizingthe water-insolublewool grease in themicelle hydrocarbonoore. In the known suint process, the efficiency of securing is limited in its eifect depending upon-the degree ofmicelle formation'of the-suint salts dissolved in the scouring medium. In our process, the addition of the neutral,v polar, oxygenated organic compound ororganic compound and electrolyte to the securing medium, by'alt'ering the dielectric constant and ionic strength of the securing medium, is believed to favor formation of suint micelles. Thus in our process, advantage is taken of factors which further the formation of micelles whereby the capacity of the suint to solubilize Wool grease is markedly increased.

(2) In the natural state, the wool grease is hydrated, that-is, each particle of the grease is surrounded by a protecting shell of water. This water acts as a barrier to the interaction of the suint salts ormicelle's and'the grease. By adding the neutral, polar, oxygenated organic compound, or organic compound plus neutral electrolyte, to the-scouring medium, this barrier is removed by the greater attractionofthe aforesaid organic compound, or organiccompound plus electrolyte, for water. After removal of this barrier, the grease can be readily solubilized by the suintsaltsor micelles.

Our invention is thus primarily directedtoan improvement in the known suint method of scouring wool wherein the suint derived'drom the wool is the active scouring agent andthe added neutral, polar, oxygenated organic compound, or organic compound plus neutral electrolyte. enhances the effectiveness of the suint as a scouring agent." However, it is not essential to utilize the'suint'a's the sole scouring agent. Thus one mayadd a soap or a synthetic detergent to the scouring medium. In such case the sanu effect is obtained as withsuint alone. i. e.. the securing action of the-added emulsifying agent (soap or synthetic detergent) is enhanced by the presence of the added neutral, polar oxygenated detergentapplications.

organic compound, or organic compound plus neutral electrolyte. fhepoint is"that the latter agent or agents increase micelle formation of whatever emulsification agent is employed and i'urther act to dehydrate the grease particles, all asdescribed hereinabove. In applying this modification of our invention, one can add to the securing medium any soap or synthetic detergent commonuly used in emulsifying and Thus, one may use any of "the well-known alkyl sulphate, alkyl sulphonate, or alkylaromatic sulphonate detergents. It is known that besides the sulphate or sulphonate group (the hydrop-hillic group) the compound must also contain a high-molecular weight hydrocarbon or hydrophobic group. There must be a balance between these opposed groups to give-the compound the requisite detergent properties. Usually the hydrocarbon group must contain about 8 to 18 carbon atoms in the caseof alkyl-sulphat'es or sulphon'a-t'e'sandiabout l l to 28 carb'on atoms inthe=case of alkyil'. arc..-

matlc sulphonates to give the proper. balance.

These compounds are generally 'ernployediin' tlie form of their salts,--i. e.-, their potassium sodium, ammonium, or amine salts. Some of the-particulardetergents which we may use are: sodium oetyl sulphate, sodium nonyl sulphate;- sodium decyl sulphate; sodiumundeoyl sulph'ate, sodium dodecyl sulph'ate,-sodium' tri'd'ecy-l sulph'ate, -so dium tetradecyl sulphate, sodium pent'adcyl sulphate, sodium hexad'ecyhsulphate; sodium heptadecyl sulphate, sodium octadecylsulphate, sodium ol'eyl' sulphate, sodium octyl sulphonate, sodium nonyl sulphonate, sodium decyl sill phonate, sodium und'e'cyl sulpho'natfe, sodium dodecyl sulphonate, sodium trideoyl sulphonate, sodium tetradecyl sulphonate, sodiiirn' pentadec'ylsulphonate, sodium hexadecylsulphonate, sodium octadeeyl sulphonate, so'diumble'yl'srilphonate, sodium-salt of di-oetyl sulphosuccinate. sodium octyl' benzene sulphonate, sodiuninony-l benzene sulphonate; sodium 'decyl benzenesulphonate, sodium' undecyl benzene sulphonate, sodium dodecyl benzene s'ulphonate, sodium tridecyl' benzene sulph'onate,- sodium tetrade'cyl benzene-sulpho'nate, sodium pentade'cyl benzene sulphonate, sodium hexadecyl benzene sul phonate, sodium heptadecyl benzene 'sulphonate. sodium octadecyl benzene sulphonate; sodium tri (isopropyl) benzene sulphonat'ei sodium'tri (isobutyl) benzene sulphonate', sodiumtri (i'so propyl) naphthalene sulph'onate, sodium tri (isobutyl) naphthalene sulphonate, and so forth. The commercially-available detergents aregem crally not pure compounds'but are 'mixtures o'f homologous c'ompound'sran d are'quite satisfactory. Thus, for example, theso'dium alkylbenzene sulph'onate, wherein the alkyl. group contains; 12 tol8flcarbon' atoms'is'a well knowndetergent. Others "are: a mixture of sodium valkyl sulphates consisting mostly of sodium lauryl sul phate; a mixtureor sodium alkyi phenol "sulpli'onates wherein the alkyl'group contains 12'to 18 carbon atoms; and a mixture of sodium al kylsulphonat'es wherein the 'alliyl group contains'10 to 18" carbon atoms; It is "evident that the'particular detergent used is not c'ritical'ex' cept that one shouldbe chosen which is generally'useful in emulsifying and detergent 'applic'ae tions. Regardless of the type of compound chosen, its eihciency to scour wool willbe enharmed by applying the teachings of this invention. r r

Many different agents within the class" of pounds.

neutral, polar, oxygenated organic compounds can be used in our process. Aliphatic alcohols having 1 to 8 carbon atoms, tetrahydrofurfuryl alcohol, and aliphatic ketones having 3 to 6 carbon atoms are included. The following are examples of suitable aliphatic alcohols and ketones in this category: methanol, ethanol, normal propanol, isopropanol, normal butanol, tertiary butanol, butanol-2, isobutanol (2- methyl-propanol-l), amyl alcohols, hexyl a1- chols, heptyl alcohols, octyl alcohols, ethylene glycol, propylene glycol, glycerol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, acetone, diacetone alcohol, methyl ethyl ketone, and so forth. If desired, mixtures can be used instead of individual corn- Thus for example the commerciallyavailable ethanol denatured with methanol is suitable.

In general, the concentration of the neutral, polar, oxygenated organic compound may be varied from about 0.1% to about 50%. The particular concentration to use in any specific situation depends on may factors as, for example, the nature of the raw wool and especially the nature of the grease and suint associated therewith, the temperature of scouring, the concentration of electrolytes in the securing solution, the micelle-forming potency of the particular organic compound used, the mechanical efliciency of the securing process as for instance the degree of agitation, number of scouring operations, efficiency of rinsing, and so forth. The concentration required in any particular case can be easily determined by scouring small samples of wool using varying concentrations of the organic solvent and noting which concentration gives the lowest residual grease content in the scoured wool. Under the conditions used in the experiments set forth in the examples we have found that the following concentrations give good results with some particular compounds:

Concentration range Approx. con giving 1subcentration s antia ingiving maxi- Compound crease in mum scourscouring ing efficiency, efliciency, percent percent Methanol 1050 40 Ethanol 5-10 n-Propanol 530 20 Isopropanol. 5-25 10 n Butanol 1-6 3 n Pentanol 0. 5-3 2. 5 n Hexanol. 0. 1-0. 6 5 Acetone 540 Methanol in presence of electrolyte. 5-40 Ethanol in presence of electrolyte 5-40 20 n-Propanol in presence of electrolyte 5-25 10 Isopropanol in presence of electrolyte.. 5-15 10 n-Butanol in presence of electrolyte. 0. 5-6 3 n-Pentanol in presence olc1ectrolyte.... 0. 25-2. 5 1 n-Hexanol in presence of electrolyte. 0. 1-0. 6 4 Acetone in presence of electrolyte"... 5-40 20 precipitation of insoluble suint salts cannot of course be used in the electrolyte. For the same reason the water used for scouring should be essentially free from calcium, magnesium, iron and similar metals, that is, the water should be soft. If only hard water is available, it is evident that a small amount of calcium-sequestering agent may be added to counteract the hardness. Suitable agents are, for example, alkali metal hexametaphosphates, citrates, pyrophosphates, etc.

The scouring treatment is generally effected Lat temperatures customarily used in securing follows: A lot of raw California wool of medium fineness was opened and blended five times in an experimental type opener. The opened wool was then homogenized by repeated hand carding and mixing. This standard wool had a shrinkage of approximately 40% and. a grease content of 12% as determined by solvent extraction. The scouring tests were performed by a standardized technique with provisions for uniform control of temperature and the degree of mechanical agitation.

Example I An aqueous solution was prepared containing 2% normal butanol and sodium chloride in a concentration of 0.1 normal.

Four hundred ml. of this solution was placed in a beaker and 3 grams of raw wool. was agitated in the solution for 3 minutes while maintaining the temperature at 60 C. The washed wool was squeezed free of solution and re washed in 400 ml. of a fresh batch of the solution again agitating for 3 minutes at 60 C. The wool was then squeezed free of solution, washed with water, dried and the grease content determined by Soxhlet extraction with benzene. The residual grease content was found to be 0.5%.

The scouring procedure as set forth above was repeatedusing different scouring solutions, i. e., ;(a) water, alone; (b) water containing varying concentrations of n-butanol; and (0) water containin sodium chloride in a concentration of 0.1 normal and varying concentrations of n-butanol. The results obtained in these experiments and those obtained from the experiment above are tabulated below:

TABLE 1 Residual grease Expt. No. Securing solution content of wool,

percent 1 (control).... water 8. 7 2. 1% n-butanol. G. 46 3.. 2% n-butanoL. 3. 06 4. 3% n-butanoL. .85 5-. 4% n-butanoL. 1.22 6 5% n-butanol 2. 52 6% n-butanol 6. 09 1% n-butanol plus 0.1 N 2% n-butanol plus 0.1 N 50 3% n-butancl plus 0.l N 7i 1% n-butanol plus 0.1 N .67 5% n-butanol plus 0.1 N NaOl 1.48

2. The process of claim 1 wherein the neutral, polar, oxygenated organic compound is isopropanel in a concentration about from 5 to 15%.

3. The process of claim 1 wherein the neutral, polar, oxygenated organic compound is n-propanol in a concentration about from 5 to 25%.

4. The process of claim 1 wherein the neutral, polar, oxygenated organic compound is n-butanol in a concentration about from 0.5 to 6%.

5. The process of claim 1 wherein the neutral, polar, oxygenated organic compound is n-amyl alcohol in a concentration about from 0.25 to 2.5%.

6. The process of claim 1 wherein the neutral, polar, oxygenated organic compound is ethanol in a concentration about from 5 to 40%.

HAROLD P. LUNDGREN. WILLIE FONG.

Name Date Barrows July 10, 1855 Number Number Number Name Date Braun May 25, 1875 Poole May 10, 1921 Duhamel June 18, 1929 Duhamel June 18, 1929 Berthold Jan. 8, 1935 Pickett et al. Nov. 2, 1937 Eitelman Nov. 19, 1940 Castendyk May 19, 1942 Leiserson July 30, 19 46 FOREIGN PATENTS Country Date Great Britain 1870 Great Britain 1909 Great Britain June 23, 1930 Great Britain July 9, 1931 Great Britain Mar. 21, 1947 OTHER REFERENCES of Raw WoolII.

The Textile Manufacturer,

January 1937, pages 5, 6, 8-139. 

1. IN THE PROCESS OF SCOURING RAW WOOL WITH AN ESSENTIALLY-NEUTRAL AQUEOUS MEDIUM WHEREIN THE ACTIVE SCOURING AGENT IS SUINT DERIVED FROM RAW WOOL, THE IMPROVEMENT WHICH COMPRISES INCORPORATING WITH THE AQUEOUS MEDIUM A NEUTRAL, POLAR, OXYGENATED ORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC ALCOHOLS HAVING 1 TO 8 CARBON ATOMS, TETRAHYDROFURFURYL ALCOHOL, AND ALIPHATIC KETONES HAVING 3 TO 6 CARBON ATOMS IN A CONCENTRATION FROM ABOUT 0.1% TO ABOUT 50%. AND A NEUTRAL, INORGANIC ELECTROLYTE SELECTED FROM THE GROUP CONSISTING OF THE WATER-SOLUBLE SALTS OF THE ALKALI METALS AND AMMONIUM IN A CONCENTRATION FROM ABOUT 0.05 TO ABOUT 0.5 NORMAL. 